Cream butter, shortening, and sugar together well, Add eggs 1 at a time blending just enough to mix, Add lemon extract and salt,______, Sprinkle baking soda and cream of tartar (sifted together) on top of the batter and fold in gently, Pour into a large greased and floured tube pan and bake at 315 degrees for 1 hour and 15 minutes, DO NOT OPEN THE OVEN UNTIL THE CAKE IS DONE, Sprinkle with powdered sugar or glaze with a favorite icing,